package io.tim.mvc_f2.helper;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import io.tim.mvc_f2.util.CollectionUtil;

/**
 * 数据库操作助手类
 *
 * @author zhangnan
 * @date 2017年3月13日
 *
 */
public final class DatabaseHelper {
	

	private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);

	private static final ThreadLocal<Connection> CONNECTION_HOLDER;
	private static final QueryRunner QUERY_RUNNER;
	private static final BasicDataSource DATA_SOURCE;

	private static final String DRIVER;
	private static final String URL;
	private static final String USERNAME;
	private static final String PASSWORD;

	static {
		CONNECTION_HOLDER = new ThreadLocal<Connection>();
		QUERY_RUNNER = new QueryRunner();
		DRIVER = ConfigHelper.getJdbcDriver();
		URL = ConfigHelper.getJdbcUrl();
		USERNAME = ConfigHelper.getJdbcUsername();
		PASSWORD = ConfigHelper.getJdbcPassword();
		
		DATA_SOURCE = new BasicDataSource();
		DATA_SOURCE.setDriverClassName(DRIVER);
		DATA_SOURCE.setUrl(URL);
		DATA_SOURCE.setUsername(USERNAME);
		DATA_SOURCE.setPassword(PASSWORD);
		
		/*

		try {
			Class.forName(DRIVER);
		} catch (ClassNotFoundException e) {
			LOGGER.error("Load JDBC Driver failure ==== ", e);
			throw new RuntimeException(e);
		}*/
	}
	
	/**
	 * 获取数据库连接
	 */
	public static Connection getConnection() {
		Connection conn = CONNECTION_HOLDER.get();
		if (conn == null) {
			try {
				conn = DATA_SOURCE.getConnection();
			} catch (SQLException e) {
				LOGGER.error("Get connection failure ==== ", e);
				throw new RuntimeException(e);
			} finally {
				CONNECTION_HOLDER.set(conn);
			}
		}
		
		return conn;
	}
	
	/**
	 * 关闭数据库连接
	 */
	/*public static void closeConnection() {
		Connection conn = CONNECTION_HOLDER.get();
		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				LOGGER.error("Close connection failure ==== ", e);
				throw new RuntimeException(e);
			} finally {
				CONNECTION_HOLDER.remove();
			}
		}
	}*/
	
	/**
	 * 执行 sql 文件
	 */
	public static void executeSqlFile(String filePath) {
		InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
		BufferedReader reader = new BufferedReader(new InputStreamReader(is));
		String sql;
		try {
			while ((sql = reader.readLine()) != null) {
				executeUpdate(sql);
			}
		} catch (IOException e) {
			LOGGER.error("execute sql file failure ==== ", e);
			throw new RuntimeException(e);
		}	
	}
	
	/**
	 * 查询实体列表
	 */
	public static <T> List<T> queryEntityList(Class<T> entityClass, String sql, Object... params) {
			List<T> entityList;
			try {
				Connection conn = getConnection();
				entityList = QUERY_RUNNER.query(conn, sql, new BeanListHandler<T>(entityClass), params);
			} catch (SQLException e) {
				LOGGER.error("query entity list failure ==== ", e);
				throw new RuntimeException(e);
			}/* finally {
				closeConnection();
			}*/
			return entityList;
	}
	
	/**
	 * 查询实体
	 */
	public static <T> T queryEntity(Class<T> entityClass, String sql, Object... params) {
			T entity;
			try {
				Connection conn = getConnection();
				entity = QUERY_RUNNER.query(conn, sql, new BeanHandler<T>(entityClass), params);
			} catch (SQLException e) {
				LOGGER.error("query entity list failure ==== ", e);
				throw new RuntimeException(e);
			}/* finally {
				closeConnection();
			}*/
			return entity;
	}
	
	/**
	 * 执行查询语句
	 */
	public static List<Map<String, Object>> executeQuery(String sql, Object... params) {
		List<Map<String, Object>> result;
		Connection conn = getConnection();
		try {
			result = QUERY_RUNNER.query(conn, sql, new MapListHandler(), params);
		} catch (SQLException e) {
			LOGGER.error("execute query failure ==== ", e);
			throw new RuntimeException(e);
		}/* finally {
			closeConnection();
		}*/
		return result;
	}
	
	/**
	 * 执行更新语句
	 */
	public static int executeUpdate(String sql, Object... params) {
		int rows;
		Connection conn = getConnection();
		try {
			rows = QUERY_RUNNER.update(conn, sql, params);
		} catch (SQLException e) {
			LOGGER.error("execute query failure ==== ", e);
			throw new RuntimeException(e);
		}/* finally {
			closeConnection();
		}*/
		return rows;
	}
	
	/**
	 * 插入实体
	 */
	public static <T> boolean insertEntity(Class<T> entityClass, Map<String, Object> fieldMap) {
		
		if (CollectionUtil.isEmpty(fieldMap)) {
			LOGGER.error("cannot insert the entity: fieldmap is empty!");
			return false;
		}
		
		String sql = "INSERT INTO " + getTableName(entityClass);
		StringBuilder columns = new StringBuilder("(");
		StringBuilder values = new StringBuilder("(");
		
		for (String fieldName : fieldMap.keySet()) {
			columns.append(fieldName).append(", ");
			values.append("?, ");
		}
		
		columns.replace(columns.lastIndexOf(", "), columns.length(), ")");
		values.replace(values.lastIndexOf(", "), values.length(), ")");
		
		sql += columns + " VALUES " + values;
		
		Object[] params = fieldMap.values().toArray();
		
		
		return (executeUpdate(sql, params) == 1);
	}
	
	/**
	 * 更新实体
	 */
	public static <T> boolean updateEntity(Class<T> entityClass, long id, Map<String, Object> fieldMap) {
		if (CollectionUtil.isEmpty(fieldMap)) {
			return false;
		}
		String sql = "UPDATE " + getTableName(entityClass) + " SET ";
		
		StringBuilder columns = new StringBuilder();
		
		for (String fieldName : fieldMap.keySet()) {
			columns.append(fieldName).append(" = ?, ");
		}
		
		sql += columns.substring(0, columns.lastIndexOf(",")) + " WHERE id = ?";
		
		List<Object> paramList = new ArrayList<Object>();
		paramList.addAll(fieldMap.values());
		paramList.add(id);
		
		Object[] params = paramList.toArray();
		return (executeUpdate(sql, params) == 1);
	}
	
	/**
	 * 删除实体
	 */
	public static <T> boolean deleteEntity(Class<T> entityClass, long id) {
		
		String sql = "DELETE FROM " + getTableName(entityClass) + " WHERE id = ?";
		return (executeUpdate(sql, id) == 1);
	}
	
	public static String getTableName(Class<?> entityClass) {
		return entityClass.getSimpleName();
	}
	
}
